The B-DECIGO as a scaled-down predecessor of DECIGO is planned to launch in 2020 [1]}.
Its noise power spectral density can be approximated by [2]}
\(S_{\rm B-DECIGO}(f)=2.02\times 10^{-48}\left[ 10^3+15.84\left( \frac{f}{{\rm Hz}} \right)^{-4}+1.584\left( \frac{f}{{\rm Hz}} \right)^2 \right]{~\rm Hz}^{-1}.\) 
